Prominence of interleaving veil areal density in modifying the mechanical response of glass epoxy laminates

This research focuses on investigating how the inclusion of interleaving veils with different areal densities influences the mechanical behavior of glass epoxy composites. Commercially available non-woven carbon veils (15, 20 and 30 g/m2) and Glass veils (25 and 30 g/m2) were used as interleaving material. The plain and interleaved composite laminates were manufactured by a hand layup process. The effect of non-woven veil interleaving was estimated through tensile, flexural, short beam shear (SBS), and single-edge notched beam (SENB) mechanical tests. The mechanical test results showed a significant variation in strength with respect to the change in the areal density of interleaving. The veil’s areal density has a significant effect on in-plane and out-of-plane composite strength. An improvement of about 6% in longitudinal tensile strength was observed for the GEC-15 C specimen. In the lateral tensile test, an improved tensile strength was observed for the veil interleaved samples. Besides, the marginal improvement was also observed for the GEC-15 C specimen under open hole tensile strength. Further, considerable enhancement of about 13%, 24%, and 44% was noticed in flexural, interlaminar shear strength (ILSS) and fracture toughness for 20 g/m2 carbon veil interleaved samples, respectively. The experimental results are presented by providing mean, standard deviation, and coefficient of variation (COV) with 4% to 10% across all the loading modes. Further, scanning electron microscopy (SEM) characterization of SENB specimen revealed that fiber pullout, matrix deformation, and fiber-matrix deboning etc., served as critical elements in improving the fracture toughness of composites reinforced with interleaving veils.